METHOD OF DISTILLATION OF WATER FROM AN AQUEOUS SALINE SOLUTION

摘要

Distilled water is produced from sea water, or other saline solution, by contacting it in heat exchanger 3 with hot mineral oil, or other water-immiscible liquid, passing the heated sea water through a multi-stage flash evaporator 2 1 .. 2 n , and condensing the vapours evolved in the higher-pressure flash stages 2 1 , 2 n , 2 n+1 , by means of oil circulating through condenser tubes in these stages, and also circulating through a heater 8 and the direct-contact heat-exchanger 3 wherein the feed sea water is heated. Before the sea water enters heat-exchanger 3, it is preheated by passing it through the condenser tubes 4 of the lower-pressure flash stages. The condensate (i.e. distilled water) is collected in trays 6, and withdrawn from the lowest-pressure stage 2 n . The oil preferably has a higher density than water. The sea water flows upwardly in dispersed form through heat-exchanger 3 and the oil flows downwardly. The condenser tubes may be made of mild steel provided with an outer coating or paint.